"Help - how can I recover D800 raw files corrupted by Nikon transfer?"

Does anyone know if there is a way to recover the files that have been transferred with Nikon transfer 1.5.3 and shows up as low res files? The files actually are 40 mb files but display as low res. Unfortunately I deleted them from memory card before I noticed and the memory card was overwritten with new pics.Thanks for your help.I have now removed the old Nikon transfer from all of my laptops.